I think you are experiencing the same problem as I have with blender 2.44 and 2.45, only that on my system (OS X 10.3.9), blender just crashes when using video in both the Compositing Nodes and the NLE. (Here my bugreport that I started back in June about this problem…)
The irony here is that I am also an editor and like you try to pitch blender and the NLE (+ Compositing Nodes) to others, in my case Final Cut Pro editors. So far two of them had trouble getting blender to run at all because of the Python thing (I don’t know yet what went wrong) and of course having a buggy video environment (see also this thread) does not help at all.
Under OS X I also can’t export video + audio except as an MPEG-2 compressed file (which I don’t need that much), all other presets crash blender or don’t do anything at all. So something is not working here at all and for the first time since I stared using blender (about 16 months ago) and I am getting a bit concerned about these issues, since now also other vital components of blender are causing serious problems for me (I just go stuck with rendering my latest animation since I get strange black and coloured dots in certain places - no solution yet for my rendering setup) or parts of the OS X build are just missing (browsing your own materials is now reduced to browsing a directory, no icons with the materials you used, not fun to work with at all) as I mentioned here a month ago.
Maybe someone more experienced can tell me that those are the usual problems you go trough when working on bigger projects, hopefully that is the case. Just right now being left with an OS X 2.45 blender that looks more and more broken does not feel nice at all… What are the options: going back to 2.43 and waiting for 2.5…? Switching to Ubuntu because OS X support is not really possible at this point…? What went wrong with 2.44 and 2.45 and why don’t we get a new build if someone finds out that certain components (like browsing your materials library) are missing…? I really want the stable blender back that I could trust and enjoyed working with - blender was so close of being the perfect all in one production tool…